1. Field of the Invention
The present invention relates, in general, to billiard/pool cues.
2. Description of the Art
Billiard/pool cues typically are formed of an elongated shaft, a butt at one end of the shaft and a ferrule mounted at an opposite end which supports a tip. The shaft may be formed as a solid, one-piece member or of two threadingly engageable sections. Typically, the shaft is formed of a hard wood, such as a hard maple.
Other materials, such as aluminum, steel, plastic and carbon fiber, have also used to form billiard/pool cue shafts. Cues formed of such "non-wood" materials have been engineered to approximate wood in weight and stiffness or rigidity; however none have proven to play better than a hard wood cue.
It has also been proposed in U.S. Pat. No. 672,646 to form cue shafts of multiple elongated pieces, such as generally pie-shaped sections, which are adhesively joined together to form a generally circular cross section which typically tapers from the butt end to a smaller diameter end supporting the ferrule and tip. In this patent, the grain of each section or strip of wood is disposed so that the dense and porous layers, which naturally alternate with each other, extend between the angled sides of each strip generally parallel to the exterior surface of each strip.
Generally a billiard/pool cue is formed with one of two styles of taper. In an "American" taper, the cue has a constant diameter of approximately 0.5 inches for approximately the first twelve inches from the tip end, this being the longest bridge length commonly used in play. The other common type of taper is a so-called "European taper". In this style of cue, the cue has a truncated cone shape along its entire length tapering to a tip size of approximately 0.35 to 0.45 inches.
Previously devised ferrules have been formed of ivory which is substantially harder than that of the material used to form the shaft. More recently, reinforced phenolics and thermoplastics have been employed to form ferrules. Such ferrules have a modulus of elasticity ranging from a high of 1.3.times.10.sup.6 psi to a low of 0.35.times.10.sup.6 psi as compared to the 1.8.times.10.sup.6 psi modulus of elasticity of hard maple commonly used to form the shaft. The ferrule is adhesively joined to and/or press fit to one end of the shaft, typically by means of a tenon in the form of a narrow diameter end portion which projects out of the end of the shaft into a hollow bore extending inward from one end of the ferrule or, alternately, from the ferrule into a bore in one end of the shaft.
The tip, which is typically formed of leather, is adhesively joined to the ferrule. Generally, the tip, according to popular practice, is formed with a large radius to present a generally flat ball contacting end portion.
In use, the shaft is lined up with the intended path of movement of the cue ball prior to stroking the shaft to impact the tip on the ball. The cue can also be lined up to strike the cue ball off center, that is, to the left or right of the center of the ball, or above or below the center of the ball, to impart spin, draw or follow to the cue ball to cause it to move in a desired direction after it strikes another ball or a rail. However, as a result of a hit to the left or right of center, the cue ball does not follow a path of movement that is parallel to the line of stroke of the cue. Rather, the cue ball deflects or moves in a path at an angle to the line of stroke of the cue. This so-called angle of deflection varies with the speed of the stroke and how far from center the cue tip strikes the cue ball, but with a given off center distance and speed, the magnitude of the angle of deflection is primarily a function of the cue itself.
As shown in FIG. 1, during off center hits, the tip, ferrule and the end of the shaft up to the player's hand bridge initially buckles as shown in phantom due to loading of the impact forces 7 generated during impact of the tip with a cue ball on the inside edge 8 of the shaft closest to the center of the ball. This buckling is then followed by an outward flexing of the tip, ferrule and shaft end. Experimentation by the Applicants has shown that a large amount of buckling results in a larger and more undesirable deflection of the cue ball from a path of movement parallel to the cue stroke line than when buckling is minimized and the end of thie cue more easily flexes or bends outward from the center of the cue ball after impact with the cue ball. FIG. 2A shows the angle of deflection of a cue ball struck to the right of center by a rigid cue. The angles A, B and C are equal to show the same spin angle and velocity. The arrow 1 shows the line of deflection of the ball from the line of stroke of the rigid cue.
In FIG. 2B, the angles A', B' and C' are equal to the angles A, B and C in FIG. 2A to denote the same spin and velocity. However, the cue in FIG. 2B is more flexible than the rigid cue in FIG. 2A. This results in a smaller overall deflection of thle cue ball from the line of stroke of the cue as shown by the arrow 2.
Tests performed by the Applicants' have determined that a hard prior art ferrule is still somewhat softer than the hard maple shaft and provides a measure of compressibility which could lower the angle of deflection of the cue ball. However, this advantage is outweighed by the increased weight of the ferrule as compared to the shaft such that the increased weight at the tip end of the shaft results in substantial deflection of the cue ball. The prior art use of an ABS ferrule appears to the Applicants' to provide a tradeoff between the compressibility of a plastic ferrule and a minimal increased weight; but the angle of deflection of a cue ball struck by such a shaft and ABS ferrule combination is about the same as that of a shaft without a ferrule.
Thus, it would be desirable to provide a billiard/pool cue which minimizes buckling while permitting easier outward flex of the tip end of the shaft to result in less deflection of a cue ball from the line of stroke of the cue shaft. It would also be desirable to provide a billiard/pool cue which has compression features to absorb impact forces generated during the impact of the cue on a ball so as to minimize buckling and permit easier outward flex of the tip end of the cue. It would also be desirable to provide a billiard/pool cue construction which centralizes the impact of the tip with a cue ball toward tlhe longitudinal axis of the shaft during off center hits to lessen buckling and to provide easier outward flex and less deflection of the struck cue ball. It would also be desirable to provide a billiard/pool cue having a lighter tip end so as to provide quick lateral acceleration of the tip end on impact for easier outward flex of the tip end and less deflection of the cue ball.